The research proposed in this application includes the following: a) ferritin-antibody experiments on section of mouse spleen cells to localize the sites of synthesis and intermediate stages in the transfer of receptor Ig and H-2 histocompatibility antigens from the inside of the cell to the plasma membrane. b) a study of the epinephrine-stimulated adenylate cyclase of pigeon erythrocytes, and the multi-hormononal stimulation of fat cells, with a view to assessing the role of membrane fluidity in cell activation. c) the effect of the attachment of specific antibody molecules directed to membrane transport proteins on the rates of transport, to determine whether the rotating carrier mechanism of translocation is correct or not. d) experiments with ferritin-antibody directed to smooth muscle myosin and other mechanochemical proteins to detect and localize such components, if they exist, on the plasma membranes of lymphocytes and other cells.